A group of individuals who share a love of cycling and the outdoors. We will always stop for a photo, or to hit a rope swing… Rubber side up!

Where did Prolly is Not Probably go?

It is still here, and then some. PiNP was one person’s opinion and voice. Now we are a collective – a community of diverse opinions and rich stories.

What does the Radavist mean?

Rad + Atavist = RADAVIST

Why does a porpoise surf a wave, or a sea otter slide down a rock? Atavism is a primal trait in humans and animals that drives us to do what we do – what ought to come naturally. Atavism is why we ride the way we ride; From mashing the city on a track bike to shredding the trails on full suspension. Take the time to get rad.

Open’s U.P. frameset has acquired quite the following since its inception and this year, Open announced the NEW and improved U.P., which this video outlines. If you have other questions, head to Open to check out the NEW U.P.

Why did this video only feature slow motion riding? It made it seem as if the bike was unstable and slow. The riders sure seemed uncomfortable and cautious on the single track. Not the best video for this bike imho.

From their website – “The seattube angle is designed around the use of a straight, zero-setback seatpost rather than a regular seatpost with setback (we’ve never understood those).”
Well that’s so you can get saddle in correct position for pedalling. I have relatively long femur for my height, so need saddle set back a lonnng way to get correct position over the pedals. I recall Vroomen mentioning skipping setback before on the Open UP and thought it a bit odd as other stuff on bike is so well thought out.

Jan Heine

My understanding is that they slacken the seat angle to compensate for the straight post. There are different ways of obtaining the same saddle position, and I understand Gerard’s point – why make a cranked seatpost to compensate for what appears to be a too-steep seat angle. I am not sure I agree – bikes are complicated machines, and things often are a certain way because they work better that way. That said, when we tested a U.P. for Bicycle Quarterly, I had no trouble pedaling up the highest pass in Japan, so at least for me, the no-setback seatpost worked well. And if you really need a huge amount of setback, you can always swap the seatpost for one with more setback.

I’m aware that a slacker seat tube angle can affect layback, but I have heaps of layback on my frame which is only 1 degree different.
It would be interesting to work out the seat tube angle that would match it with an inline post. But a more relaxed seat tube angle could reduce tyre clearance.
The seat tube angle on my frame also varies with size going from a steep 75.5 for the smallest size to a more relaxed 72.5 for the largest size, which make sense as that reflects the relative leg length and getting correct the saddle position over the saddle. The largest frame is the same as on the Open UP which is a constant 72.5 for all sizes.

Regardless as I’d love to try an Open UP because it’s close to the perfect single bike. And if it fitted me….
Not that I want just one bike, you understand. ;) But I am trying to get more minimal.

Gerard Vroomen

Sure, often things work a certain way because it’s better, and sometimes because it made sense centuries ago and just was never changed. Like cars having two front lights because then you can see one on each side of the horse that pulls it, or train tracks being a width that corresponds with how the Romans made their chariots.

Maybe what I should write is that it is silly that the DEFAULT setup of a seattube+seatpost is to have 25mm setback on the post. The default should not be to have the angle going one way and then needing an offset in the post to correct that. And the only reason that is really the case because in the previous century, the way seat posts were made it was easier to make them with a setback. Since that is no longer the case (seat post saddle clamps no longer use single bolts with cerated cradles), there is also no reason to adhere to that “standard”.

As for tire clearance, that’s not really related to these angles as there is no reason the seat tube cannot have any other clearance-creating shape down there, or be offset from the BB, or …..

As for different seat tube angles on different sizes, that has very little (being nice) to do with different leg lengths. Those leg lengths are already taken into account with a fixed angle, that’s the beauty of angles. With a lower saddle it also moves forward, also making the seat tube steeper is doubly compensating for that. The main reason that happens is to avoid toe-overlap while still giving people the idea that their frame is shorter. That’s the great benefit of stack & reach, that it so clearly points out the fallacy of making smaller frames by shortening the toptube and steepening the seat tube at the same time, one counteracting the other to create the frame that isn’t any shorter.